That is special the case with the DN2540 or other depletion mosfets.
Nice work X I have now with the circlotron also very low distortion, -120dB when output 2 amps, the DN2540 is cleaner, and needs higher idle, that is why drain resistors are 680 ohm in stead of 1.5k.
regards
Please see one the finest Aksa Lender Preamp builds by Gtose in GB thread:
https://www.diyaudio.com/forums/gro...der-preamp-40vpp-ouput-gb-41.html#post5576044
Powering Super MoFo in his main system:
https://www.diyaudio.com/forums/gro...der-preamp-40vpp-ouput-gb-41.html#post5576044
Powering Super MoFo in his main system:
Got mine working today. Powered it up and it worked first time. 🙂
It still needs some work on the chassis, but I listened for a few hours and apart from more volume due to the gain (about 15dB. R11 = 2K2), I can hear an improvement in the soundstage and imaging. I've been using a B1 buffer up till now and really got used to how the ACA and B1 sounds on the 0.53x Karlsonators with dual 3FE25-16's. The AKSA Lender's sound is different - in a good way.
Thanks to Hugh, X and JP for making this design available. You guys rock.
It still needs some work on the chassis, but I listened for a few hours and apart from more volume due to the gain (about 15dB. R11 = 2K2), I can hear an improvement in the soundstage and imaging. I've been using a B1 buffer up till now and really got used to how the ACA and B1 sounds on the 0.53x Karlsonators with dual 3FE25-16's. The AKSA Lender's sound is different - in a good way.
Thanks to Hugh, X and JP for making this design available. You guys rock.
Attachments
Beautiful work, Skylar! That’s a nice layout you have there and I see you even made the input selector panel. Glad it worked the first time. If the ACA is about 14dB gain, and the Aksa Lender Preamp is 15dB, you have 29dB of total gain which is about the usual gain for most amps designed to be driven by line level sources. If you like less gain just increase the ground shunt resistor R11 to 3k3 maybe?
Skylar88,
Echoing X's comments on the layout, very tidy and elegant inside. 🙂
The chassis that you're working with, is it a standard make or custom? What are the dimensions?
Echoing X's comments on the layout, very tidy and elegant inside. 🙂
The chassis that you're working with, is it a standard make or custom? What are the dimensions?
Real nice work Skylar88!!
I like that you included the power supply in the enclosure with a conventional ac switched input.
Congratulations
I like that you included the power supply in the enclosure with a conventional ac switched input.
Congratulations
Thanks guys. I'm please with how this project turned out. The amount of gain seems right, X.
No comments about the two separate pots? 😀
It's a feature that got carried over from the B1 because I like to have balance control.
@zman1
It's a custom made alu box that I've had for many years from an aborted non-audio project. The box was much too high, so I had to chop the top 60% off and then I had to build a bending brake to make a new lid. The new size is 225 x 175 x 71 high with the lid on.
I had two of these boxes and used the other for the B1 one last year.
No comments about the two separate pots? 😀
It's a feature that got carried over from the B1 because I like to have balance control.
@zman1
It's a custom made alu box that I've had for many years from an aborted non-audio project. The box was much too high, so I had to chop the top 60% off and then I had to build a bending brake to make a new lid. The new size is 225 x 175 x 71 high with the lid on.
I had two of these boxes and used the other for the B1 one last year.
Skylar,
One of the best preamps I have ever seen, beautifully, almost factory assembly.
Preamps are difficult because there are lots of inputs, controls, and metal holes. Lots of wire too, and tricky to keep them quiet.
The EI transformer is outstanding in this role because at low power the magnetic field is well controlled, important for a preamp.
Congratulations!!
Hugh
One of the best preamps I have ever seen, beautifully, almost factory assembly.
Preamps are difficult because there are lots of inputs, controls, and metal holes. Lots of wire too, and tricky to keep them quiet.
The EI transformer is outstanding in this role because at low power the magnetic field is well controlled, important for a preamp.
Congratulations!!
Hugh
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Thanks Hugh. It really means a lot to me, coming from Mr AKSA himself.
I also need to thank all the diyAudio members who contribute to this and the GB thread, clarifying preamp building mysteries. As a relatively new audio hobbyist, I still have a lot of questions.
I'm really enjoying this preamp. Never expected it to be this good! 😀
I also need to thank all the diyAudio members who contribute to this and the GB thread, clarifying preamp building mysteries. As a relatively new audio hobbyist, I still have a lot of questions.
I'm really enjoying this preamp. Never expected it to be this good! 😀
I'm thinking to replace the carbon pots on my freshly built AKSA Lender preamp with Cermet pots. This was decided after reading Hugh's FAQ's.
If I want to "law fake" a linear Cermet pot with a simple 15 KOhm resistor, should I start out with a 100K pot as described in the FAQ's? Will this work on the AKSA Lender Pre or should I start with a different value pot?
If I want to "law fake" a linear Cermet pot with a simple 15 KOhm resistor, should I start out with a 100K pot as described in the FAQ's? Will this work on the AKSA Lender Pre or should I start with a different value pot?
Skylar,
One thing to do is to listen for a while, maybe a week or two and listen for negative effects of your pots on sonic quality. One quick test is to put pots on max, thereby effectively bypassing them and use your DAC output (via software or knob on DAC) as volume control. Then set DAC at some reasonable near max output (80%) and use pot on preamp as volume control. Can you hear degraded sound vs setting of max volume?
I use Alps stereo linear 10k pots from RK09 series (circa $5ea). They have nicely machined aluminum shaft. They use carbon tracks on polymer substrate (I know because I accidentally popped one open by pushing a volume knob onto the shaft with too much force). They sound very good to me, but I am not a volume pot aficionado.
You will find that this preamp is smooth and has no scratchy sound when adjusting the pot. The RK09 seems to be well balanced left and right too.
One thing to do is to listen for a while, maybe a week or two and listen for negative effects of your pots on sonic quality. One quick test is to put pots on max, thereby effectively bypassing them and use your DAC output (via software or knob on DAC) as volume control. Then set DAC at some reasonable near max output (80%) and use pot on preamp as volume control. Can you hear degraded sound vs setting of max volume?
I use Alps stereo linear 10k pots from RK09 series (circa $5ea). They have nicely machined aluminum shaft. They use carbon tracks on polymer substrate (I know because I accidentally popped one open by pushing a volume knob onto the shaft with too much force). They sound very good to me, but I am not a volume pot aficionado.
You will find that this preamp is smooth and has no scratchy sound when adjusting the pot. The RK09 seems to be well balanced left and right too.
Thanks X, I did the quick test that you've suggested. I used 50%, 80% and then full pot travel, with the media player adjusted for the same volume on all three settings.
For my playlist I chose simple tracks like Katie Melua - I'd Love To Kill You, Nicolaj Grandjean - Heroes & Saints, and Craig Chaquico - Gypsy Nights. I could not hear any distortion or other nasties. They sound superb on all three settings with an amazing soundstage, exceptional imaging and good layering. What a preamp! 😱
Thanks Jerry, for coercing my into building it. 😛
I've already ordered Bourns Series 91 Cermet pots with metal shafts, so I'm anyway going to replace these Alpha (Taiwan) pots and keep them for a future project.
For my playlist I chose simple tracks like Katie Melua - I'd Love To Kill You, Nicolaj Grandjean - Heroes & Saints, and Craig Chaquico - Gypsy Nights. I could not hear any distortion or other nasties. They sound superb on all three settings with an amazing soundstage, exceptional imaging and good layering. What a preamp! 😱
Thanks Jerry, for coercing my into building it. 😛
I've already ordered Bourns Series 91 Cermet pots with metal shafts, so I'm anyway going to replace these Alpha (Taiwan) pots and keep them for a future project.
Well it sounds like your Alpha Taiwan pots are decent quality. I know budget $0.25 pots can sound terrible. But I have heard people say the best pot is no pot! 🙂 for me though, a $5 to $10 seems to be good enough.
Components should be arriving any day now..... Just need to check the forum for any changes / corrections since I ordered the parts. If nothing, I'll make a start next weekend.
Nice work Zman. I usually try to test it on the bench before putting it in a case. It makes debugging a lot easier. I would at least power it up and check to make sure bias current on daughterboards are good.
H2 predominance test
I think you should to do this test:
Do you like tube distortion? - listening test
I think you should to do this test:
Do you like tube distortion? - listening test